diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_init_q15.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_init_q15.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_init_q15.c b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_init_q15.c new file mode 100644 index 0000000..66c69c0 --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_init_q15.c @@ -0,0 +1,137 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_fir_init_q15.c
+ * Description: Q15 FIR filter initialization function
+ *
+ * $Date: 18. March 2019
+ * $Revision: V1.6.0
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "arm_math.h"
+
+/**
+ @ingroup groupFilters
+ */
+
+/**
+ @addtogroup FIR
+ @{
+ */
+
+/**
+ @brief Initialization function for the Q15 FIR filter.
+ @param[in,out] S points to an instance of the Q15 FIR filter structure.
+ @param[in] numTaps number of filter coefficients in the filter. Must be even and greater than or equal to 4.
+ @param[in] pCoeffs points to the filter coefficients buffer.
+ @param[in] pState points to the state buffer.
+ @param[in] blockSize number of samples processed per call.
+ @return execution status
+ - \ref ARM_MATH_SUCCESS : Operation successful
+ - \ref ARM_MATH_ARGUMENT_ERROR : <code>numTaps</code> is not greater than or equal to 4 and even
+
+ @par Details
+ <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
+ <pre>
+ {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
+ </pre>
+ Note that <code>numTaps</code> must be even and greater than or equal to 4.
+ To implement an odd length filter simply increase <code>numTaps</code> by 1 and set the last coefficient to zero.
+ For example, to implement a filter with <code>numTaps=3</code> and coefficients
+ <pre>
+ {0.3, -0.8, 0.3}
+ </pre>
+ set <code>numTaps=4</code> and use the coefficients:
+ <pre>
+ {0.3, -0.8, 0.3, 0}.
+ </pre>
+ Similarly, to implement a two point filter
+ <pre>
+ {0.3, -0.3}
+ </pre>
+ set <code>numTaps=4</code> and use the coefficients:
+ <pre>
+ {0.3, -0.3, 0, 0}.
+ </pre>
+ <code>pState</code> points to the array of state variables.
+ <code>pState</code> is of length <code>numTaps+blockSize</code>, when running on Cortex-M4 and Cortex-M3 and is of length <code>numTaps+blockSize-1</code>, when running on Cortex-M0 where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_q15()</code>.
+ */
+
+arm_status arm_fir_init_q15(
+ arm_fir_instance_q15 * S,
+ uint16_t numTaps,
+ const q15_t * pCoeffs,
+ q15_t * pState,
+ uint32_t blockSize)
+{
+ arm_status status;
+
+#if defined (ARM_MATH_DSP)
+
+ /* The Number of filter coefficients in the filter must be even and at least 4 */
+ if (numTaps & 0x1U)
+ {
+ status = ARM_MATH_ARGUMENT_ERROR;
+ }
+ else
+ {
+ /* Assign filter taps */
+ S->numTaps = numTaps;
+
+ /* Assign coefficient pointer */
+ S->pCoeffs = pCoeffs;
+
+ /* Clear the state buffer. The size is always (blockSize + numTaps ) */
+ memset(pState, 0, (numTaps + (blockSize)) * sizeof(q15_t));
+
+ /* Assign state pointer */
+ S->pState = pState;
+
+ status = ARM_MATH_SUCCESS;
+ }
+
+ return (status);
+
+#else
+
+ /* Assign filter taps */
+ S->numTaps = numTaps;
+
+ /* Assign coefficient pointer */
+ S->pCoeffs = pCoeffs;
+
+ /* Clear state buffer. The size is always (blockSize + numTaps - 1) */
+ memset(pState, 0, (numTaps + (blockSize - 1U)) * sizeof(q15_t));
+
+ /* Assign state pointer */
+ S->pState = pState;
+
+ status = ARM_MATH_SUCCESS;
+
+ return (status);
+
+#endif /* #if defined (ARM_MATH_DSP) */
+
+}
+
+/**
+ @} end of FIR group
+ */
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